Pulmonary edema is a condition caused by excess fluid in the lungs. This fluid collects in the numerous air sacs in the lungs, making it difficult to breathe. The most common cause of pulmonary edema is heart problems, but fluid can accumulate for other reasons, including pneumonia, exposure to certain toxins and medications, and exercising or living at high elevations.
Pulmonary edema that develops suddenly (acute) is a medical emergency requiring immediate care, and can sometimes prove fatal. Treatment for pulmonary edema varies depending on the cause, but generally includes supplemental oxygen and medications, and may require both acute treatments along with ambulatory treatment for the underlying problem.
Oxidative stress and inflammatory responses are key features of pulmonary edema and exercise-induced pulmonary hemorrhage (EIPH). Neutrophils and hemosiderophages (macrophages that have ingested and digested red blood cells) are present in high numbers in the lungs of animals suffering from EIPH, indicating an influx of inflammatory cells. Similarly, hypoxia has been highly implicated
Pulmonary edema is of particular concern in elite athletes. For example, EIPH is an endemic production disease form of pulmonary edema of racing and other high-intensity exercise horses, which occurs when blood enters the air passages of a horse's lung, which may lead to the impairment of lung function. EIPH or “bleeding” has been a recognized condition in racing horses for at least three hundred years, and has been reported to occur in a variety of race horse breeds including racing Thoroughbreds (both flat racing and steeple chasing or jump racing), American Quarter Horses (incidence of 50-75%), Standardbreds (incidence of 40-60%), Arabians, and Appaloosas. EIPH has also been reported in eventers, jumpers, polo ponies, endurance horses, draft horses that pull competitively, and horses taking part in Western speed events such as reining, cutting and barrel racing. Virtually all horses that are subjected to intense exercise bleed into the lungs, and these episodes of bleeding often commence as soon as these horses enter training, making EIPH a major welfare and economic concern to both veterinarians, and those involved in the racing and sport horse industries. Healing occurs, but complete restoration of pulmonary function in the affected area often does not occur. Repeated episodes of intense exercise can result in repeated episodes of pulmonary hemorrhage, and cumulative damage to the affected lung tissue can occur such as e.g., fibrosis and/or scaring and consolidation of alveoli. These chronic changes occur, particularly in the dorso-caudal lobes of the lung, and such changes can eventually curtail the performance of the horse.
Preventative/ameliorative/curative/restorative measures for EIPH affected horses have also been sought for several hundred years. For many years, the treatment of choice for prevention of EIPH in the race horse has been pre-race treatment with the diuretic furosamide (Lasix®). However, the exact mechanism of action of furosamide in prevention of EIPH is unknown, although many theories have been postulated over the years, its effectiveness is in question, and its use in racing is illegal in all countries with the exceptions of the U.S. and Canada. The treatment of choice for EIPH, after the fact, is usually rest (mandatory in many racing jurisdictions) and often in conjunction with antibiotics to prevent secondary bacterial infection and/or the use of anti-inflammatory medication.
More recently, (following the research of West et al. J. Appl. Physiol. 1993, 75: 1097-1109 related to the relationship of EIPH and increased pulmonary artery pressure) attempts at treating EIPH via nitric oxide administration have been tried, e.g., by Perry (U.S. Pat. No. 5,765,548). Perry describes administration of nitric oxide through continuous insufflation of the nitric oxide to the horse during the exercise period. Alternatively, the horse is treated with insufflation of nitric oxide prior to the exercise event and then is given an intramuscular injection of a phosphodiesterase inhibitor, e.g., ZAPRINAST. The treatment during exercise as described by Perry is both cumbersome and problematic for the racing animal and has never gained widespread acceptance. Likewise, systemic treatment of the racing animal with phosphodiesterase inhibitors opens the door for unwanted side effects and requires regulatory scrutiny.
Histone deacetylases (HDACs) are a class of enzymes that remove acetyl groups (O═C≦CH3) from an ε-N-acetyl lysine amino acid on a histone, allowing the histones to wrap the DNA more tightly. Together with the acetylpolyamine amidohydrolases and the acetoin utilization proteins, the histone deacetylases form an ancient protein superfamily known as the histone deacetylase superfamily. HDACs are classified in four classes depending on sequence homology to the yeast original enzymes and domain organization. The Class I HDACs are HDAC1, HDAC2, HDAC3, and HDAC8. The Class IIA HDACs are HDAC4, HDAC5, HDAC7, and HDAC9. The Class IIB HDACs are HDAC6 and HDAC10. Class III HDACs include the sirtuin proteins (SIRT1-7). The HDAC11 is the Class IV HDAC. HDACs in Classes I, II, and IV (HDACs1-11) are metal-dependant HDACs. By modulating the acetylation status of histones, histone deacetylase inhibitors alter the transcription of genes involved in cell growth, maturation, survival and apoptosis, among other processes. In addition to histones, HDACs have many non-histone protein substrates which have a role in regulation of gene expression, cell proliferation, cell migration, cell death, and angiogenesis.
The organosulfur compound L-sulforaphane (LSF) is obtained from cruciferous vegetables (such as broccoli, Brussels sprouts or cabbages) when hydrolytic conversion of glucoraphanin to sulforaphane through the action of physical damage to the plant occurs either by the action of plant-derived myrosinase (intracellular broccoli thioglucosidase), or by the microbiota of the human colon. Approximately, 60-80% of glucoraphanin is converted to sulforaphane, with most broccoli varieties possessing between 0.1 and 30 μmol/g of glucoraphanin.
LSF is known to have potent antioxidant effects by activation of the Nrf2-ARE detoxification pathway. Nrf2 is a CNC (cap ‘n’ collar) bZIP (basic region leucine zipper) group of transcription factors which is broadly expressed in a variety of tissues. Quiescent Nrf2 localizes in the cytoplasm and is rapidly turned over through a specific ubiquitin-26S proteasome pathway controlled by the Keap1/Cul3-independent ubiquitin ligase (E3). Nrf2 is activated in response to a range of oxidative and electrophilic stimuli including ROS, heavy metals and certain disease processes. Upon activation, Nrf2 mediates antioxidant response by the induction of a broad range of genes including phase 2 enzymes, such as NAD(P)H:quinone oxidoreductase 1 (NQO1) and heme oxygenase-1, and antioxidant proteins, such as SOD and catalase. Both genetic and biochemical studies have implicated the Nrf2 signaling pathway in the defense against a wide range of chemical toxicity, cancer and chronic diseases in which oxidative stress is involved. LSF has been shown to protect against oxidative stress and apoptosis by the induction of Nrf2-mediated antioxidant response.
Therefore, it is a primary object, feature, or advantage of the present invention to improve upon the state of the art.
It is a further object, feature, or advantage of the present invention to provide methods of treating and/or preventing diseases associated with inflammation. In one aspect, the methods of treating and/or preventing diseases associated with inflammation involve providing or administering an effective amount of L-sulforaphane to a subject in need thereof. The L-sulforaphane may be combined with other components, including, for example, antioxidant or anti-inflammatory compounds. In a particular embodiment, L-sulforaphane can be administered or provided in combination with one or more of hydroxytyrosol, oleuropein, N-acetylcysteine, L-proline, glycine, and taurine.
It is a further objective, feature or advantage of the present invention to provide methods of treating and/or preventing pulmonary edema, including for example EIPH. In one aspect, the methods of treating and/or preventing pulmonary edema involve providing or administering an effective amount of L-sulforaphane to a subject in need thereof. The L-sulforaphane may be combined with other components, including, for example, antioxidant or anti-inflammatory compounds. In one embodiment, the methods involve providing or administering a nasal spray.
It is a further objective, feature or advantage of the present invention to provide compositions and methods for inhibiting HDACs. In one aspect the compositions and methods provide specific inhibition of Class I HDACs, and in particular embodiments specific inhibition of HDAC8.
It is a further objective, feature or advantage of the present invention to provide compositions and methods for altering gene expression in a cell, tissue, or subject, including by increasing lysine acetylation, and/or increasing or decreasing gene expression in cells or tissues contacted with an LSF containing composition. These methods may be used for improving cell viability and/or treating or preventing oxidative stress in an individual or cell.